package com.googlecode.cswish.util;

import java.security.MessageDigest;

import org.apache.log4j.Logger;

public class MD5Encrypt {
	private static final Logger logger = Logger.getLogger(MD5Encrypt.class);
	
	public MD5Encrypt() {
	}

	private static final String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	/**
	 * convert byte array to hex string
	 * 
	 * @param b
	 * @param hexEnc
	 * @return
	 */
	public static String byteArrayToString(byte[] b, boolean hexEnc) {
		StringBuffer resultSb = new StringBuffer();
		if (!hexEnc) {
			for (int i = 0; i < b.length; i++) {
				resultSb.append(byteToNumString(b[i]));
			}
		} else {
			for (int i = 0; i < b.length; i++) {
				resultSb.append(byteToHexString(b[i]));
			}
		}
		return resultSb.toString();
	}

	private static String byteToNumString(byte b) {
		int _b = b;
		if (_b < 0) {
			_b = 256 + _b;
		}

		return String.valueOf(_b);
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0) {
			n = 256 + n;
		}
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String encode(String origin) {
		String resultString = null;

		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			byte[] encBytes = md.digest(origin.getBytes());
			resultString = byteArrayToString(encBytes, true);
		} catch (Exception ex) {
			logger.error(ex);
		}
		return resultString;
	}
}
